“…In each of the four districts, principals (and sometimes assistant principals) attended district-sponsored professional development sessions on both high-quality mathematics instruction (sometimes with their teachers or math coaches), as well as on observation and feedback routines. While the research is scant, there is evidence that school leaders can learn content-specific leadership practices through professional development (Barth, 1986; Boston, Henrick, Gibbons, Berebitsky, & Colby, 2016; Carver, Steele, & Herbel-Eisenmann, 2010; Nelson, 1997; Sassi & Nelson, 1999). Given these districts’ ambitious goals for instructional improvement and infrastructures of support (discussed in detail below), they presented promising sites for exploring how administrators might work as part of a coherent instructional system to support teachers’ development of ambitious practice (Cobb & Jackson, 2011a).…”